Synthesis of a New Chromogenic Reagent 4-Methyl-2-Sulfobenzenediazoam inoazobenzene (MSDAA) and Study on Its Color Reaction with Cadmium(II)

The method of synthesis of the new chromogenic reagent 4 methyl 2 sulfobenzenediazoaminoazobenzene and the conditions of its color reaction with cadmium(Ⅱ) have been investigated.It was found that the reagent reacted with cadmium(Ⅱ) to form a red complex with a molar ratio of 3∶1 in ammoniacal buffer solution(pH10 8) in the presence of nonionic surfactant Triton X 100 The maximum absorption of the complex is at 522nm and the apparent molar absorptivity is 2 05×10 5 L·mol -1 ·cm -1 .Beer's law is obeyed for 0～20μg of cadmium in 25 mL solution.This mothod has been employed to determine trace amount of cadmium(Ⅱ) in waste water with satisfactory results.